Conductive ball mounting apparatus and conductive ball mounting method

ABSTRACT

In a conductive ball mounting apparatus for mounting one conductive ball on each of a plurality of pads which are provided on a substrate and on which an adhesive is formed, the conductive ball mounting apparatus includes: a conductive ball container for containing a plurality of conductive balls therein and having an opening to pass through the plurality of conductive balls; a substrate holder disposed over the conductive ball container to face the opening, and holding the substrate in such a manner that the plurality of conductive balls and the plurality of pads face each other and the substrate is disposed over the conductive ball container with a space therebetween; and a conductive ball supplying unit for supplying the plurality of conductive balls to the plurality of pads via the opening by moving up the plurality of conductive balls.

This is a divisional application of copending application Ser. No.12/042,916, filed on Mar. 5, 2008, which is incorporated by referenceherein in its entirety.

This application is based on and claims priority from Japanese PatentApplications No. 2007-057785, filed on Mar. 7, 2007, No. 2007-137939,filed on May 24, 2007, and No. 2008-37732, filed on Feb. 19, 2008, theentire contents Of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure relates to a conductive ball mounting apparatusand a conductive ball mounting method and, more particularly, aconductive ball mounting apparatus and a conductive ball mounting methodfor mounting conductive balls on a substrate such as a wiring substrate,a wafer, or the like having a plurality of pads on which an adhesive isformed thereon.

2. Background Art

FIG. 1 to FIG. 6 are step views describing a conductive ball mountingmethod in the related-art.

A conductive ball mounting method in the related-art will be describedwith reference to FIG. 1 to FIG. 6 hereunder. At first, in steps shownin FIG. 1, a flux 102 is formed on a plurality of pads 101 provided on asubstrate 100, and also a resist film 103 is formed on portions of thesubstrate 100 positioned between a plurality of pads 101.

Then, in steps shown in FIG. 2, the mask 106 having a plurality ofopenings 106A is fixed on the resist film 103. The openings 106A areformed to expose the pads 101.

Then, in steps shown in FIG. 3, a plurality of conductive balls 108 aredisposed on the mask 106. Then, in steps shown in FIG. 4, one conductiveball 108 is mounted on the pads 101 on which the flux 102 is formedrespectively by vibrating the substrate 100.

Then, in steps shown in FIG. 5, extra conductive balls 108 that have notbeen mounted on the pads 101 are removed by sweeping an upper surface ofthe mask 106 by a squeegee 110. Then, in steps shown in FIG. 6, the mask106 is removed. Accordingly, the substrate 100 having the conductiveballs 108 on the pads 101 is formed (see e.g., JP-A-11-297886).

However, in the method of mounting the conductive ball 108 in therelated-art, the step of mounting one conductive ball 108 on the pads101 on which the flux 102 is formed respectively and the step ofremoving the extra conductive balls 108 by sweeping an upper surface ofthe mask 106 by the squeegee 110 are performed separately. Therefore,such a problem existed that it is difficult to improve productivity inthe step of mounting the conductive ball 108 on the pads 101 and thestep of removing the extra conductive balls 108.

In addition, Japanese Patent Application Publication: JP-A-2-102538discloses another conductive ball mounting method. In JP-A-2-102538, aconductive layer on which a solder bump is formed is formed on onesurface of a circuit substrate and also a solder-flux layer is formed onthe one surface of the circuit substrate. Then, a spacer is formed onthe solder-flux layer and a mask having openings is formed on thespacer. Next, the circuit substrate is disposed on a solder ballcontainer for accommodating solder balls such that the one surface ofthe circuit substrate opposes to an opening formed in the solder ballcontainer. Finally, the solder balls are mounted on the circuitsubstrate by vibrating the solder ball container hard (see FIG. 1 ofJP-A-2-102538).

However, in the conductive ball mounting method disclosed in therelated-art, rapid vibration is required to mount the solder balls onthe openings of the mask. In this case, force caused by the rapidvibration is also applied to the circuit substrate (the mask).Especially, upon using a large substrate, a thin substrate or smallballs whose diameter is 100 μm or less, thickness of the mask becomesthin and thus the mask is more likely to vibrate. Therefore, defect suchas displacement of the solder balls is generated by vibration of themask (the circuit substrate).

SUMMARY OF THE INVENTION

One or more exemplary embodiments of the present invention provide aconductive ball mounting apparatus and a conductive ball mounting methodthat can improve productivity by reducing a processing time required forthe step of mounting a conductive ball on a plurality of padsrespectively and the step of removing extra conductive balls.

According to one or more aspects of the present invention, a conductiveball mounting apparatus for mounting one conductive ball on each of aplurality of pads which are provided on a substrate and on which anadhesive is formed, the conductive ball mounting apparatus comprises:

a conductive ball container for containing a plurality of conductiveballs therein and having an opening to pass through the plurality ofconductive balls;

a substrate holder disposed over the conductive ball container to facethe opening, and holding the substrate in such a manner that theplurality of conductive balls and the plurality of pads face each otherand the substrate is disposed over the conductive ball container with aspace therebetween; and

a conductive ball supplying unit for supplying the plurality ofconductive balls to the plurality of pads via the opening by moving upthe plurality of conductive balls.

According to the present invention, the extra conductive balls, whichare not disposed on the pads on which the adhesive is formed, out of theplurality of moved-up conductive balls fall down on the conductive ballcontainer. Therefore, the step of mounting the conductive ball on theplurality of pads respectively and the step of removing extra conductiveballs can be carried out simultaneously. As a result, a processing timerequired for the step of mounting the conductive ball on the pluralityof pads respectively and the step of removing the extra conductive ballscan be shortened, and thus productivity can be improved.

According to one or more aspects of the present invention, a conductiveball mounting apparatus for mounting one conductive ball on each of aplurality of pads which are provided on a substrate and on which anadhesive is formed, the conductive ball mounting apparatus comprises:

a conductive ball for container for containing a plurality of conductiveballs therein and having an opening to pass through the plurality ofconductive balls;

a substrate holder for holding the substrate such that the plurality ofconductive balls and the plurality of pads face each other in adirection perpendicular to a gravity direction; and

a conductive ball supplying unit for supplying the plurality ofconductive balls to the plurality of pads by spraying the plurality ofconductive balls.

According to the present invention, the extra conductive balls, whichare not disposed on the pads on which the adhesive is formedrespectively, out of the plurality of conductive balls sprayed to theplurality of pads fall down in the gravity direction. Therefore, thestep of mounting the conductive ball on the plurality of padsrespectively and the step of removing the extra conductive balls can beperformed at the same time. As a result, a processing time required forthe step of mounting the conductive ball on the plurality of padsrespectively and the step of removing the extra conductive balls can beshortened, and productivity can be improved.

According to one or more aspects of the present invention, a mask mayhave a plurality of through portions corresponding to positions wherethe plurality of pads are formed, and the mask may be provided to thesubstrate such that each of the pads is exposed from the plurality ofthrough portions, and a diameter of the through portions may be set to asize capable of passing only one conductive ball.

Therefore, it can be prevented that the plurality of conductive ballsare mounted on one pad.

According to one or more aspects of the present invention, theconductive ball mounting apparatus further comprises:

a potential difference generating unit for generating a potentialdifference between the plurality of conductive balls contained in theconductive ball container and the substrate.

Therefore, the plurality of moved-up conductive balls supplied by theconductive ball supplying unit are attracted to the substrate by anelectrical attractive force. As a result, a processing time in the stepof mounting one conductive ball on a plurality of pads respectively canbe shortened.

According to one or more aspects of the present invention, theconductive ball mounting apparatus further comprises:

a charging unit for charging the mask up to a potential that issubstantially equal to a potential of the plurality of conductive ballscontained in conductive ball container.

Therefore, the plurality of raised conductive balls are attracted to thepads by an electrical attractive force. As a result, a processing timein the step of mounting the conductive ball on the plurality of padsrespectively can be further shortened.

According to one or more aspects of the present invention, theconductive ball mounting apparatus further comprises:

a conductive ball recovering container for recovering extra conductiveballs that are not disposed on the pads and fall down in the gravitydirection, the conductive ball recovering container being disposed belowthe substrate in the gravity direction.

According to one or more aspects of the present invention, a method formounting one conductive ball on each of a plurality of pads which areprovided on a substrate and on which an adhesive is formed, the methodcomprises the successive steps of:

(a) disposing the substrate over a conductive ball container forcontaining the plurality of conductive balls therein with a spacetherebetween such that the plurality of conductive balls and theplurality of pads face each other; and

(b) supplying the plurality of conductive balls to the plurality of padsby moving up the plurality of conductive balls.

According to the present invention, the extra conductive balls, whichare not disposed on the pads on which the adhesive is formed, out of theplurality of moved-up conductive balls fall down on the conductive ballcontainer. Therefore, the step of mounting the conductive ball on theplurality of pads respectively and the step of removing extra conductiveballs can be carried out at the same time. As a result, a processingtime required for the step of mounting the conductive ball on theplurality of pads respectively and the step of removing the extraconductive balls can be shortened, and thus productivity can beimproved.

According to one or more aspects of the present invention, a method formounting one conductive ball on each of a plurality of pads which areprovided on a substrate and on which an adhesive is formed, the methodcomprises the successive steps of:

(a) disposing the substrate such that a plurality of conductive ballsand the plurality of pads face each other in a direction perpendicularto a gravity direction; and

(b) supplying the plurality of conductive balls to the plurality of padsby spraying the plurality of conductive balls.

According to the present invention, the extra conductive balls, whichare not disposed on the pads on which the adhesive is formedrespectively, out of the plurality of conductive balls sprayed to themask fall in the gravity direction. Therefore, the step of mounting theconductive ball on the plurality of pads respectively and the step ofremoving the extra conductive balls can be performed simultaneously. Asa result, a processing time required for the step of mounting theconductive ball on the plurality of pads respectively and the step ofremoving the extra conductive balls can be shortened, and productivitycan be improved.

According to one or more aspects of the present invention, the methodfurther comprises:

(c) providing a mask having a plurality of through portionscorresponding to positions where a plurality of pads are formed, beforestep (a).

According to one or more aspects of the present invention, the methodfurther comprises:

(d) providing a mask having a plurality of through portions such thatthe mask covers an opening of a conductive ball container where theplurality of conductive balls are contained, before step (a).

According to one or more aspects of the present invention, the methodfurther comprises:

(e) generating a potential difference between the plurality ofconductive balls contained in the conductive ball container and thesubstrate, between step (a) and step (b).

Therefore, the plurality of conductive balls are attracted to thesubstrate by an electrical attractive force. As a result, a processingtime in the step of mounting one conductive ball on the plurality ofpads respectively can be shortened.

According to one or more aspects of the present invention, the methodfurther comprises:

(f) charging the mask up to a potential that is substantially equal to apotential of the plurality of conductive balls contained in theconductive ball container, between step (a) and step (b).

Therefore, the plurality of conductive balls are attracted to the padsby an electrical attractive force. As a result, a processing time in thestep of mounting the conductive ball on the plurality of padsrespectively can be further shortened.

According to one or more exemplary embodiments of the present invention,productivity can be improved by reducing a processing time in the stepof mounting conductive balls on a plurality of pads and the step ofremoving extra conductive balls.

According to one or more exemplary embodiments of the present invention,the substrate is disposed over the conductive ball container with aspace therebetween, so that defect such as displacement of solder ballscan be suppressed.

Other aspects and advantages of the invention will be apparent from thefollowing description, the drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a step view (#1) describing a conductive ball mounting methodin the related-art;

FIG. 2 is a step view (#2) describing the conductive ball mountingmethod in the related-art;

FIG. 3 is a step view (#3) describing the conductive ball mountingmethod in the related-art;

FIG. 4 is a step view (#4) describing the conductive ball mountingmethod in the related-art;

FIG. 5 is a step view (#5) describing the conductive ball mountingmethod in the related-art;

FIG. 6 is a step view (#6) describing the conductive ball mountingmethod in the related-art;

FIG. 7 is a sectional view of a conductive ball mounting apparatusaccording to a first embodiment of the present invention;

FIG. 8 is a step view (#1) describing a conductive ball mounting methodusing the conductive ball mounting apparatus according to the firstembodiment of the present invention;

FIG. 9 is a step view (#2) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 10 is a step view (#3) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 11 is a step view (#4) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 12 is a step view (#5) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 13 is a step view (#6) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 14 is a step view (#7) describing the conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention;

FIG. 15 is a sectional view of a conductive ball mounting apparatusaccording to a second embodiment of the present invention;

FIG. 16 is a sectional view of a conductive ball mounting apparatusaccording to a third embodiment of the present invention;

FIG. 17 is a sectional view of a conductive ball mounting apparatusaccording to a fourth embodiment of the present invention;

FIG. 18 is a sectional view of a conductive ball mounting apparatusaccording to a fifth embodiment of the present invention; and

FIG. 19 is a sectional view of a conductive ball mounting apparatusaccording to a sixth embodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention will be described withreference to the drawings hereinafter.

First Embodiment

FIG. 7 is a sectional view of a conductive ball mounting apparatusaccording to a first embodiment of the present invention. In FIG. 7,such a situation is illustrated that a plurality of conductive balls 14are caused to move up the lower side of a substrate 18 held by asubstrate holder 15. Also, in FIG. 7, Z direction denotes the verticaldirection, and X direction denotes the direction that intersectsorthogonally with the Z direction.

By reference to FIG. 7, a conductive ball mounting apparatus 10 of thefirst embodiment includes a stage 11, a vibrating unit 12 as aconductive ball supplying unit, a conductive ball container 13, aplurality of conductive balls 14, and the substrate holder 15 forholding the substrate 18.

At first, for brief description, a structure of the substrate 18 held bythe substrate holder 15 will be described hereunder. The substrate 18 isconstructed such that a plurality of substrates 25 are formed on aplate-like substrate main body 26. That is, the substrate 18 is anaggregate of the plurality of substrates 25 prior to diving intoindividual pieces. As the substrate main body 26, a glass epoxy resinmay be used.

The substrate 25 has the substrate main body 26, through vias 28, upperwirings 29, pads 31, 35, solder resists 32, 37, lower wirings 34, andadhesives 38. The through via 28 is provided to pass through thesubstrate main body 26. An upper end portion of the through via 28 isconnected to the pad 31, and a lower end portion of the through via 28is connected to the pad 35.

The upper wirings 29 are provided on an upper surface 26A of thesubstrate main body 26. The upper wirings 29 are connected to the pads31. The pads 31 are provided on portions, which correspond to positionswhere the through via 28 is formed, of the upper surface 26A of thesubstrate main body 26. The pad 31 is connected to the through vias 28respectively. The pads 31 are provided to mount an electronic component(e.g., a passive component, or the like). The solder resist 32 isprovided on the upper surface 26A of the substrate main body 26 to coverthe upper wirings 29. The solder resist 32 has openings 32A to exposethe pads 31.

The lower wirings 34 are provided on a lower surface 26B of thesubstrate main body 26. The lower wirings 34 are connected to the pads35. The pads 35 are provided on portions, which correspond to positionswhere the through via 28 is formed, of the lower surface 26B of thesubstrate main body 26. The pad 35 is connected to the through vias 28respectively. The pads 35 are connected electrically to the pads 31 viathe through vias 28. One conductive ball 14 serving as an externalconnection terminal of the substrate 25 is provided on the pad 35 viathe adhesive 38.

The solder resist 37 is provided on the lower surface 26B of thesubstrate main body 26 to cover the lower wirings 34. The solder resist37 has openings 37A to expose the pads 35. The adhesive 38 is providedon the pads 35 to fill the openings 37A. The adhesive 38 is used totemporarily fix the conductive balls 14 that are caused to move up whenthe vibrating unit 12 vibrates the conductive ball container 13. As theadhesive 38, the flux, the solder paste may be used.

The substrate 18 constructed as above is held by the substrate holder 15such that a plurality of pads 35 on which the adhesive 38 is formedrespectively are opposed to a plurality of conductive balls 14 exposedfrom openings 13A.

The stage 11 supports the conductive ball container 13 via the vibratingunit 12. The vibrating unit 12 is provided on the stage 11. Thevibrating unit 12 vibrates the conductive ball container 13 containing aplurality of conductive balls 14 to move up the plurality of conductiveballs 14, and thus supplies the plurality of conductive balls 14 to thesubstrate 18 arranged over the conductive ball container 13.

Since such the vibrating unit 12 moves up the plurality of conductiveballs 14 from the lower side of the substrate 18, extra conductive balls14, which are not disposed on the pads 35 on which the adhesive 38 isformed, out of the plurality of moved up conductive balls 14 fall downon the conductive ball container 13. Therefore, the step of mounting theconductive ball 14 on the plurality of pads 35 respectively and the stepof removing extra conductive balls 14 can be performed at the same time.As a result, a processing time required for the step of mounting theconductive ball 14 on the plurality of pads 35 respectively and the stepof removing the extra conductive balls 14 can be shortened, andproductivity can be improved.

The conductive ball container 13 is provided to contain the plurality ofconductive balls 14. The opening 13A for passing the plurality ofconductive balls 14 moved up by the vibrating unit 12 through there isformed on the upper end portion of the conductive ball container 13. Theplurality of conductive balls 14 passing through the conductive ballcontainer 13 reach the substrate 18 and are disposed on the pads 35 onwhich the adhesive 38 is formed respectively. As the material of theconductive ball container 13, a metal may be used.

A plurality of conductive balls 14 are contained in the conductive ballcontainer 13. The conductive balls 14 act as the external connectionterminals of the substrate 25. As the conductive ball 14, a solder ballmay be used. Also, when the solder ball is used as the conductive ball14, a diameter of the conductive ball 14 may be set to 10 μm to 100 μm,for example.

The substrate holder 15 is disposed over the conductive ball container13. The substrate holder 15 has a substrate holding portion 21, and asupport 22. The substrate holding portion 21 is disposed such that itslower surface 21A faces the opening 13A of the conductive ball container13. The substrate holding portion 21 is formed into a plate shape. Thesubstrate holding portion 21 holds the substrate 18 on its lower surface21A. As the method of holding the substrate 18, suction, mechanicalholding (e.g., clamping) may be used. Also, a distance D1 between theadhesives 38 of the substrate 18 held by the substrate holding portion21 and the plurality of conductive balls 14 contained in the conductiveball container 13 may be set to 1 mm, for example. The support 22 isprovided to support the substrate holding portion 21.

According to the present embodiment, the conductive ball mountingapparatus includes: the conductive ball container 13 for containing aplurality of conductive balls 14 therein and also having the opening 13Ato supply the plurality of conductive balls 14; the substrate holder 15disposed over the conductive ball container 13 to face the opening 13Aand for holding the substrate 18 such that a plurality of conductiveballs 14 and a plurality of pads 35 are opposed to each other; and thevibrating unit 12 for moving up the plurality of conductive balls 14.Thus, the extra conductive balls 14, which are not disposed on the pads35 on which the adhesive 38 is formed, out of the plurality of moved-upconductive balls 14 fall down on the conductive ball container 13.Therefore, the step of mounting the conductive ball 14 on the pluralityof pads 35 respectively and the step of removing extra conductive balls14 may be carried out simultaneously. As a result, a processing timerequired for the step of mounting the conductive ball 14 on theplurality of pads 35 respectively and the step of removing the extraconductive balls 14 can be shortened, and thus productivity can beimproved.

FIG. 8 to FIG. 14 are step views describing a conductive ball mountingmethod using the conductive ball mounting apparatus according to thefirst embodiment of the present invention. In FIG. 8 to FIG. 14, thesame reference symbols are denoted to the same constituent portions asthe configuration shown in FIG. 7. Also, in FIG. 8, FIG. 13, and FIG.14, “A” denotes a position where the substrate 18 is divided intoindividual pieces (referred to as a “cut position A” hereinafter).

The method of mounting the conductive balls 14 using the conductive ballmounting apparatus 10 according to the first embodiment of the presentinvention will be described with reference to FIG. 8 to FIG. 14hereunder.

At first, in steps shown in FIG. 8, the substrate 18 where the adhesive38 is provided on a plurality of pads 35 respectively is formed by thewell-known approach. Then, in steps shown in FIG. 9, a plurality ofconductive balls 14 are filled in the conductive ball container 13.

Then, in steps shown in FIG. 10, the substrate 18 is held by thesubstrate holding portion 21 such that the substrate 18 is disposed overthe conductive ball container 13 with a space therebetween. Thesubstrate holding portion 21 is disposed over the plurality ofconductive balls 14 such that the plurality of conductive balls 14 andthe plurality of pads 35 on which the adhesive 38 is providedrespectively face each other (substrate disposing step).

Then, in steps shown in FIG. 11, the plurality of conductive balls 14are provided to the plurality of pads 35 by vibrating the conductiveball container 13 by means of the vibrating unit 12 to move up theplurality of conductive balls 14 contained in the conductive ballcontainer 13 (conductive ball providing step).

Accordingly, the extra conductive balls 14, which are not disposed onthe pads 35 on which the adhesive 38 is formed, out of the plurality ofraised conductive balls 14 fall down on the conductive ball container13. Therefore, the step of mounting the conductive ball 14 on theplurality of pads 35 respectively and the step of removing extraconductive balls 14 can be carried out simultaneously. As a result, aprocessing time required for the step of mounting the conductive ball 14on the plurality of pads 35 respectively and the step of removing theextra conductive balls 14 can be shortened, and thus productivity can beimproved.

In this case, the vibration of the conductive ball container 13 by thevibrating unit 12 is continued until the conductive ball 14 is mountedon all pads 35 respectively.

Then, in steps shown in FIG. 12, the vibration of the conductive ballcontainer 13 by the vibrating unit 12 is stopped after the conductiveball 14 is mounted on all pads 35 respectively.

Then, in steps shown in FIG. 13, the substrate 18 on which theconductive balls 14 are mounted is released from the substrate holdingportion 21. Then, the conductive balls 14 and the pads 35 are joinedtogether by heating a structure shown in FIG. 13, and then the adhesive38 is cleaned.

Then, in steps shown in FIG. 14, the structure shown in FIG. 13 is cutalong the cut position A. As a result, a plurality of substrates 25having the conductive balls 14 are formed.

According to the conductive ball mounting method of the presentembodiment, the plurality of conductive balls 14 are moved up to thelower side of the substrate 18 being held such that the plurality ofconductive balls 14 and a plurality of pads 35 on which the adhesive 38is provided respectively face each other. Thus, the extra conductiveballs 14, which are not disposed on the pads 35 on which the adhesive 38is formed, out of the plurality of raised conductive balls 14 fall downon the conductive ball container 13. Therefore, the step of mounting theconductive ball 14 on the plurality of pads 35 respectively and the stepof removing extra conductive balls 14 can be carried out at the sametime. As a result, a processing time required for the step of mountingthe conductive ball 14 on the plurality of pads 35 respectively and thestep of removing the extra conductive balls 14 can be shortened, andthus productivity can be improved.

In the present embodiment, the case where the vibrating unit 12 is usedas the conductive ball supplying unit is described by way of example.But any means may be employed as the conductive ball supplying unit ifsuch means can move up the plurality of conductive balls 14. Forexample, in place of the vibrating unit 12, an air supplying unit formoving up the plurality of conductive balls 14 by supplying an air maybe employed.

Second Embodiment

FIG. 15 is a sectional view of a conductive ball mounting apparatusaccording to a second embodiment of the present invention. In FIG. 15,such a situation is illustrated that a plurality of conductive balls 14are moved up to the lower side of the substrate 18 held by the substrateholder 15. Also, in FIG. 15, the same reference symbols are denoted tothe same constituent portions as those of the conductive ball mountingapparatus 10 in the first embodiment.

By reference to FIG. 15, a conductive ball mounting apparatus 45 of thesecond embodiment is constructed similarly to the conductive ballmounting apparatus 10 except that a mask 46 is provided to theconfiguration of the conductive ball mounting apparatus 10 in the firstembodiment. Also, the mask 46 is disposed over the conductive ballcontainer 13 with a space therebetween.

The mask 46 is fixed to the substrate 18 via a resist film 47 formed onthe solder resist 37. The mask 46 has through portions 46A. A pluralityof through portions 46A are formed to pass through portions, whichcorrespond to positions where the pad 35 is formed respectively, of themask 46. The through portions 46A are formed to expose the pads 35. Adiameter R1 of the through portion 46A is set to a size through whichonly one conductive ball 14 can pass (a size larger slightly than adiameter of the conductive ball 14). Concretely, when a diameter of theconductive ball 14 is 100 μm, a diameter R1 of the through portion 46Acan be set to 120 μm, for example. Also, the material of the mask 46, ametal may be used.

According to the conductive ball mounting apparatus of the presentembodiment, the mask 46 having the plurality of through portions 46A inportions corresponding to positions where a plurality of pads 35 areformed is fixed to the substrate 18, and also a diameter R1 of thethrough portion 46A is set to a size through which only one conductiveball 14 can pass. Therefore, such a situation can be prevented that theplurality of conductive balls 14 are disposed on one pad 35 on which theadhesive 38 is formed.

When the conductive ball mounting apparatus 45 of the present embodimentis used, the conductive ball 14 can be mounted on the plurality of pads35 respectively by the similar approach to the method of mounting theconductive ball 14 described in the first embodiment.

According to the conductive ball mounting method of the presentinvention, the mask 46 having the plurality of through portions 46A inportions corresponding to positions where the plurality of pads 35 areformed is fixed to the substrate 18, and then the plurality ofconductive balls 14 are moved up. Therefore, a diameter R1 of thethrough portion 46A is set to a size through which only one conductiveball 14 can pass. As a result, such a situation can be prevented thatthe plurality of conductive balls 14 are mounted on one pad 35 on whichthe adhesive 38 is formed.

Also, such a situation can be prevented by using the mask 46 that theplurality of conductive balls 14 come into collision with respectiveportions of the substrate 18 on which the adhesive 38 is not formed.Therefore, it can be prevented that the substrate 18 is damaged onaccount of the collision of the conductive ball 14.

Third Embodiment

FIG. 16 is a sectional view of a conductive ball mounting apparatusaccording to a third embodiment of the present invention. In FIG. 16,such a situation is illustrated that a plurality of conductive balls 14are moved up to the lower side of the substrate 18 held by the substrateholder 15. Also, in FIG. 16, the same reference symbols are denoted tothe same constituent portions as those of the conductive ball mountingapparatus 45 in the second embodiment.

By reference to FIG. 16, a conductive ball mounting apparatus 50according to the third embodiment is constructed similarly to theconductive ball mounting apparatus 45 except that a potential differencegenerating unit 51 and insulating members 52A, 52B are provided to theconfiguration of the conductive ball mounting apparatus 45 in the secondembodiment.

The potential difference generating unit 51 has a power supply 54 andwirings 56 to 58. The power supply 54 has a plus terminal 54A and aminus terminal 54B. The plus terminal 54A is connected electrically tothe substrate 18 via the wiring 56. Accordingly, the substrate 18 is setto a plus potential. The minus terminal 54B is connected to a ground viathe wiring 57. Accordingly, the minus terminal 54B is set to a groundpotential.

One end portion of the wiring 56 is connected to the substrate 18whereas the other end is connected to the plus terminal 54A. One endportion of the wiring 57 is connected to the minus terminal 54B whereasthe other end is connected to a ground. One end portion of the wiring 58is connected to the wiring 57 whereas the other end is connected to theconductive ball container 13. Accordingly, the conductive ball container13 and a plurality of conductive balls 14 contained in the conductiveball container 13 are set to a ground potential.

The potential difference generating unit 51 constructed as above isprovided to generate a potential difference between the plurality ofconductive balls 14 contained in the conductive ball container 13 andthe substrate 18. A potential difference generated between a pluralityof conductive balls 14 and the substrate 18 may be set such that anelectrical attractive force generated between the plurality ofconductive balls 14 and the substrate 18 by the potential differenceexceeds a gravity applied to the conductive balls 14. Concretely, thepotential difference generated between the plurality of conductive balls14 and the substrate 18 may be set to several hundreds V to tens ofthousands V, for example.

In this manner, the potential difference generating unit 51 forgenerating a potential difference between the plurality of conductiveballs 14 contained in the conductive ball container 13 and the substrate18 is provided. Thus, the plurality of moved-up conductive balls 14 areattracted to the substrate 18 by an electrical attractive force. As aresult, a processing time in the step of mounting the conductive ball 14on the plurality of pads 35 respectively can be shortened.

The insulating member 52A is provided between the vibrating unit 12 andthe conductive ball container 13. The insulating member 52A is providedto make the charging of the plurality of conductive balls 14 containedin the conductive ball container 13 easy. The insulating member 52B isprovided between the substrate holding portion 21 and the support 22.The insulating member 52B is provided to insulate the substrate holdingportion 21 and the support 22 mutually.

According to the conductive ball mounting apparatus of the presentembodiment, the potential difference generating unit 51 for generatingthe potential difference between the plurality of conductive balls 14contained in the conductive ball container 13 and the substrate 18 isprovided. Thus, the plurality of moved-up conductive balls 14 areattracted to the substrate 18 by an electrical attractive force. As aresult, a processing time required for the step of mounting theconductive ball 14 on a plurality of pads 35 respectively can bereduced.

When the conductive ball mounting apparatus 50 of the present embodimentis used, the conductive ball 14 can be mounted on the plurality of pads35 respectively by the similar approach to the method of mounting theconductive ball 14 in the first embodiment, except that a potentialdifference is generated between the plurality of conductive balls 14contained in the conductive ball container 13 and the substrate 18 (thepotential difference generating step) in the steps shown in FIG. 10 andFIG. 11 in the first embodiment.

According to the conductive ball mounting method of the presentembodiment, the plurality of conductive balls 14 are moved up after apotential difference is generated between the plurality of conductiveballs 14 contained in the conductive ball container 13 and the substrate18 (the potential difference generating step). Therefore, the pluralityof raised conductive balls 14 are attracted to the substrate 18 by anelectrical attractive force. As a result, a processing time in the stepof mounting the conductive ball 14 on the plurality of pads 35respectively can be reduced.

In the present embodiment, the case where the plurality of conductiveballs 14 contained in the conductive ball container 13 are set to aground potential and the substrate 18 is set to a plus potential isdescribed as an example. But the substrate 18 may be set to a groundpotential and the plurality of conductive balls 14 may be set to a pluspotential.

Fourth Embodiment

FIG. 17 is a sectional view of a conductive ball mounting apparatusaccording to a fourth embodiment of the present invention. In FIG. 17,such a situation is illustrated that a plurality of conductive balls 14are moved up to the lower side of the substrate 18 held by the substrateholder 15. Also, in FIG. 17, the same reference symbols are denoted tothe same constituent portions as those of the conductive ball mountingapparatus 50 in the third embodiment.

By reference to FIG. 17, a conductive ball mounting apparatus 60 of thefourth embodiment is constructed similarly to the conductive ballmounting apparatus 50 except that a charging unit 61 is further providedto the configuration of the conductive ball mounting apparatus 50 in thethird embodiment. In the present embodiment, the case where a wiring isused as the charging unit 61 will be described below.

One end portion of the charging unit 61 is connected to the wiring 57whereas the other end portion is connected to the mask 46. Accordingly,the mask 46 is set to a ground potential that is substantially equal toa potential of the plurality of conductive balls 14 contained in theconductive ball container 13.

According to the conductive ball mounting apparatus, there are providedthe potential difference generating unit 51 for generating a potentialdifference between the plurality of conductive balls 14 contained in theconductive ball container 13 and the substrate 18 and the charging unit61 for making a potential of the mask 46 substantially equal to apotential of the plurality of conductive balls 14 contained in theconductive ball container 13. Therefore, the plurality of moved-upconductive balls 14 are attracted to the pads 35 by an electricalattractive force. As a result, a processing time in the step of mountingthe conductive ball 14 on the plurality of pads 35 respectively can befurther shortened.

When the conductive ball mounting apparatus 60 of the present embodimentis used, the conductive ball 14 can be mounted on the plurality of pads35 respectively by the similar approach to the method of mounting theconductive ball 14 in the first embodiment except that a potentialdifference is generated between the plurality of conductive balls 14contained in the conductive ball container 13 and the substrate 18 (thepotential difference generating step) and a potential of the mask 46 ismade substantially equal to a potential of the plurality of conductiveballs 14 contained in the conductive ball container 13 (the maskcharging step), in the steps shown in FIG. 10 and FIG. 11 in the firstembodiment.

According to the conductive ball mounting method of the presentembodiment, the plurality of conductive balls 14 are moved up after apotential difference is generated between the plurality of conductiveballs 14 contained in the conductive ball container 13 and the substrate18 (the potential difference generating step) and a potential of themask 46 is made substantially equal to a potential of the plurality ofconductive balls 14 contained in the conductive ball container 13 (themask charging step). Therefore, the plurality of moved-up conductiveballs 14 are attracted to the pads 35 by an electrical attractive force.As a result, a processing time in the step of mounting the conductiveball 14 on the plurality of pads 35 respectively can be further reduced.

Fifth Embodiment

FIG. 18 is a sectional view of a conductive ball mounting apparatusaccording to a fifth embodiment of the present invention. In FIG. 18,such a situation is illustrated that a plurality of conductive balls 14are sprayed to the substrate 18, on which the mask 46 is provided, fromthe direction that intersects orthogonally with the vertical direction(Z-direction). Also, in FIG. 18, the same reference symbols are denotedto the same constituent portions as those of the conductive ballmounting apparatus 45 in the second embodiment.

By reference to FIG. 18, a conductive ball mounting apparatus 70 of thefifth embodiment is constructed similarly to the conductive ballmounting apparatus 45, except that a supporting table 71, a conductiveball container 72, an air supplying unit 73 as the conductive ballsupplying unit, and a conductive ball recovering container 74 areprovided instead of the stage 11, the vibrating unit 12, and theconductive ball container 13 provided to the conductive ball mountingapparatus 45 of the second embodiment and except that the substrate 18is held by the substrate holder 15 such that openings 76A of theconductive ball container 72 and the pads 35 face each other in adirection perpendicular to the vertical direction (Z, Z direction).

The supporting table 71 is provided to support the conductive ballcontainer 72 and the air supplying unit 73. The conductive ballcontainer 72 has a front plate 76 and a rear plate 77. The conductiveball container 72 is disposed such that the front plate 76 faces aplurality of pads 35. The front plate 76 has a plurality of openings76A. The openings 76A are formed to pass through portions of the frontplate 76, which face to the pads 35. When a diameter of the conductiveball 14 is 100 μm, a diameter R2 of the opening 76A may be set to 150μm, for example. Also, a distance D2 between the front plate 76 and theadhesive 38 may be set to 1 mm, for example.

The rear plate 77 has a plurality of air introduction ports 77A. The airintroduction ports 77A are formed to pass through portions, which faceto the openings 76A, of the rear plate 77. The plurality of airintroduction ports 77A are provided to introduce an air supplied fromthe air supplying unit 73 into the conductive ball container 72.

The air supplying unit 73 is provided on the supporting table 71 andcontacts the rear plate 77 of the conductive ball container 72. The airsupplying unit 73 is the unit that supplies an air into the conductiveball container 72 via the air introduction ports 77A. The air supplyingunit 73 supplies an air into the conductive ball container 72 to spray aplurality of conductive balls 14 to the substrate 18, on which the mask46 is provided, (concretely, the plurality of pads 35) via the openings76A in such a manner that one conductive ball 14 is mounted on theplurality of pads 35 respectively.

The extra conductive balls 14, being not disposed on the pads 35 onwhich the adhesive 38 is formed respectively, out of the plurality ofconductive balls 14 sprayed to the substrate 18 fall down in thevertical direction by virtue of gravity. Therefore, the step of mountingthe conductive ball 14 on the plurality of pads 35 respectively and thestep of removing the extra conductive balls 14 can be performed at thesame time. As a result, a processing time required for the step ofmounting the conductive ball 14 on the plurality of pads 35 respectivelyand the step of removing the extra conductive balls 14 can be shortened,and productivity can be improved.

The conductive ball recovering container 74 is disposed below thesubstrate 18. An upper end portion of the conductive ball recoveringcontainer 74 is open. The conductive ball recovering container 74 isprovided to recover the extra conductive balls 14 that are not disposedon the pads 35 and fall down in the vertical direction by virtue ofgravity. In this manner, the recovered conductive balls 14 can be reusedby providing the conductive ball recovering container 74.

According to the present embodiment, the conductive ball mountingapparatus includes: the conductive ball container 72 for containing theplurality of conductive balls 14 and having the plurality of openings76A to supply the plurality of conductive balls 14; the substrate holder15 for holding the substrate 18 such that the openings 76A of theconductive ball container 72 and the pads 35 face each other in adirection perpendicular to the vertical direction (Z direction); and theair supplying unit 73 for spraying the plurality of conductive balls 14to the plurality of pads 35. Therefore, the extra conductive balls 14,which are not disposed on the pads 35 on which the adhesive 38 is formedrespectively, out of the plurality of conductive balls 14 sprayed to thesubstrate 18 fall down in the vertical direction by virtue of gravity.As a result, the step of mounting the conductive ball 14 on theplurality of pads 35 respectively and the step of removing the extraconductive balls 14 can be carried out simultaneously.

Accordingly, a processing time required for the step of mounting theconductive ball 14 on the plurality of pads 35 respectively and the stepof removing the extra conductive balls 14 can be shortened, andproductivity can be improved.

When the conductive ball mounting apparatus 70 of the present embodimentis used, the conductive ball 14 can be mounted on the plurality of pads35 respectively by the similar approach to the method of mounting theconductive balls 14 described in the first embodiment, except that theplurality of conductive balls 14 are supplied to the substrate 18 by anair supplied from the air supplying unit 73 in the steps shown in FIG.11 in the first embodiment.

According to the conductive ball mounting method of the presentembodiment, the substrate 18 is held such that the openings 76A and thepads 35 face each other in a direction perpendicular to the verticaldirection (Z direction), and then the plurality of conductive balls 14are sprayed to the plurality of pads 35 by the air supplying unit 73.Therefore, the extra conductive balls 14, which are not disposed on thepads 35, out of the plurality of conductive balls 14 sprayed to thesubstrate 18 fall down in the vertical direction by virtue of gravity.As a result, the step of mounting the conductive ball 14 on theplurality of pads 35 respectively and the step of removing the extraconductive balls 14 can be performed at the same time.

Accordingly, a time required for the step of mounting the conductiveball 14 on the plurality of pads 35 respectively and the step ofremoving the extra conductive balls 14 can be reduced shorter than therelated-art. As a result, productivity can be improved in the step ofmounting the conductive ball 14 on the plurality of pads 35 respectivelyand the step of removing the extra conductive balls 14.

Also, the potential difference generating unit 51 (see FIG. 16)described in the third embodiment may be provided to the conductive ballmounting apparatus 70 of the present embodiment. In this case, thesimilar advantages to those of the conductive ball mounting apparatus 50in the third embodiment can be achieved.

Here, the potential difference generating unit 51 (see FIG. 16)described in the third embodiment and the charging unit 61 (see FIG. 17)described in the fourth embodiment may be provided to the conductiveball mounting apparatus 70 of the present embodiment. In this case, thesimilar advantages to those of the conductive ball mounting apparatus 60in the fourth embodiment can be achieved.

Sixth Embodiment

FIG. 19 is a sectional view of a conductive ball mounting apparatusaccording to a sixth embodiment of the present invention. In FIG. 19,such a situation is illustrated that a plurality of conductive balls 14are moved up to the lower side of the substrate 18 held by the substrateholder 15. Also, in FIG. 19, the same reference symbols are denoted tothe same constituent portions as those of the conductive ball mountingapparatus 45 in the second embodiment.

By reference to FIG. 19, a conductive ball mounting apparatus 80 of thesixth embodiment is constructed similarly to the conductive ballmounting apparatus 45, except that a plate 81 and a containing stage 82are provided instead of the mask 46 and the stage 11 provided to theconductive ball mounting apparatus 45 in the second embodiment andexcept that the resist film 47 provided in the conductive ball mountingapparatus 45 is removed from the constituent elements.

The containing stage 82 has a containing portion 82A to contain thevibrating unit 12 and the conductive ball container 13 therein. Thecontaining stage 82 contacts the lower end portion of the vibrating unit12. The containing stage 82 supports the conductive ball container 13via the vibrating unit 12.

The plate 81 is provided to the containing stage 82, and is disposedover the conductive ball container 13. The plate 81 has a plurality ofthrough portions 81A. The through portions 81A are formed to passthrough portions, which face to the pads 35, of the plate 81. The plate81 having the plurality of through portions 81A is the mask used to emitthe conductive balls 14 toward the adhesive 38 being formed on the pads35 respectively. When a diameter of the conductive ball 14 is 100 μm, adiameter of the through portion 81A may be set to 120 μm, for example.As the material of the plate 81, a metal may be used.

According to the conductive ball mounting apparatus of the presentembodiment, the containing stage 82 for containing the vibrating unit 12and the conductive ball container 13 therein is provided, and also theplate 81 having the through portions 81A that emit the conductive balls14 toward the adhesive 38 being formed on the pads 35 respectively isprovided to the containing stage 82. Therefore, the conductive balls 14can be mounted more easily than the case where the conductive ball 14 ismounted on the pads 35, on which the adhesive 38 is formed respectively,by fitting the mask 46 on the substrate 18 via the resist film 47, andalso productivity can be improved in the conductive ball mounting step.

The method of mounting the conductive ball 14 of the present embodimentcan be carried out by the similar approach to the method of mounting theconductive ball 14 of the second embodiment. The method of mounting theconductive ball 14 of the present embodiment can achieve the similaradvantages to those of the method of mounting the conductive balls 14 inthe second embodiment.

While there has been described in connection with the exemplaryembodiments of the present invention, it will be obvious to thoseskilled in the art that various changes and modification may be madetherein without departing from the present invention. It is aimed,therefore, to cover in the appended claim all such changes andmodifications as fall within the true spirit and scope of the presentinvention.

The present invention is applicable to the conductive ball mountingapparatus and the conductive ball mounting method for mounting theconductive balls on the substrate having the plurality of pads on whichan adhesive is formed thereon.

1. A conductive ball mounting apparatus for mounting one conductive ballon each of a plurality of pads which are provided on a substrate and onwhich an adhesive is formed, the conductive ball mounting apparatuscomprising: a conductive ball container configured to contain aplurality of conductive balls therein and having an opening throughwhich the plurality of conductive balls pass; a substrate holderdisposed vertically above the conductive ball container in the directionof gravity to face the opening, and holding the substrate in such amanner that the plurality of conductive balls and the plurality of padsface each other and the substrate is disposed vertically above theconductive ball container in the direction of gravity with a spacetherebetween; and a conductive ball supplying unit configured to supplythe plurality of conductive balls to the plurality of pads via theopening by vertically moving the plurality of conductive balls againstthe force of gravity by vibrating the conductive ball container, whereina solder resist having a plurality of openings is provided on thesubstrate such that each of the openings exposes a corresponding one ofthe pads.
 2. The conductive ball mounting apparatus according to claim1, wherein a mask has a plurality of through portions corresponding topositions where the plurality of pads are formed, and the mask isprovided to the substrate such that each of the pads is exposed from theplurality of through portions, and a diameter of the through portions isset to a size capable of passing only one conductive ball.
 3. Theconductive ball mounting apparatus according to claim 1, furthercomprising: a potential difference generating unit configured togenerate a potential difference between the plurality of conductiveballs contained in the conductive ball container and the substrate. 4.The conductive ball mounting apparatus according to claim 3, furthercomprising: a charging unit configured to charge the mask up to apotential that is substantially equal to a potential of the plurality ofconductive balls contained in conductive ball container.